[Infective endocarditis: considerations regarding optimal timing for surgical treatment]. / Endokarditis: Entscheidungshilfen für den optimalen Zeitpunkt zur operativen Sanierung.

BACKGROUND: Treatment of infective endocarditis is primarily conservative. Persistent infection, tissue destruction und hemodynamic instabilities argue - in dependence on the microorganisms involved - for an urgent surgical treatment, even when there is still no control of the local and systemic infection. For timing of the surgical intervention, the following suggestions seem to be valid: TIMING OF THE SURGICAL INTERVENTION: Delayed surgical indication is considered a prognostic factor of extraordinary relevance for surgical treatment of infective endocarditis. Presence of intramyocardial, paravalvular and root abscess or development of a septic cardiomyopathy (in addition to the valve-related disturbed pump and muscular function), systemic sepsis and irreversible extracardiac organ destruction (liver, spleen, kidney, brain, lung, bone, etc.) reduce the surgical prognosis even after successful and complete surgical treatment. Extracardiac foci may determine the postoperative course. After cerebral embolization the cardiac operation should be performed as early as possible (within 24-48 h after embolization). Extreme extent of cardiac and extracardiac tissue destruction due to delayed surgical indication can result in a situation, where adequate surgical treatment of the local focus is not likely to be successful anymore and prognosis becomes infaust. In their own patients, the authors observed: NYHA (New York Heart Association) III-IV > 50%; renal failure (dialysis) > 15%, systemic embolization > 30%, cerebral embolization > 8%, cardiogenic shock > 10%. SURGICAL TREATMENT: The most important aspect is complete debridement of all infected tissue with a safety margin of about 3 mm. This holds true, even if it results in resection of the entire aortic root, mitral ring, aortic wall, and atrial tissue. There is no contraindication to the implantation of prosthetic materials (valves, bovine pericardium, mitral rings) as long as surgical debridement has been prompt and aggressive. Not the type of prosthesis, but the quality of surgical debridement is of prognostic relevance. Reconstructive techniques are suggested whenever possible and are primarily effective for the treatment of mitral and tricuspid valves. Prompt and aggressive eradication of extracardiac foci is important to the patient's postoperative course. POSTOPERATIVE COURSE AND TIMING OF THE OPERATION: After successful surgical treatment of the intracardiac focus, the postoperative course is mainly determined by extracardiac foci, systemic sepsis, and persistent secondary organ destruction. PERSPECTIVE: As the results of conservative treatment of infective endocarditis are still not satisfactory, in some subgroups improved surgical results due to aggressive and radical debridement of infective tissue (with a safety margin of at least 3 mm) will suggest the surgical treatment option even in those patients, that have primarily been considered for conservative treatment.

Evidence for a negative inotropic effect of obesity in human myocardium?

OBJECTIVE: The present study was performed as an attempt to analyze the relationship between body weight and human myocardial performance. As overweight is frequently associated with hypertension, stenosis of epimyocardial coronary arteries and other factors that influence myocardial performance, the experimental model of isolated human atrial myocardium was selected. Atrial contractile performance does neither depend on the extent of stenosis of epicardial coronary arteries nor on the degree of hypertension and its secondary pathology. METHODS: Right atrial muscle preparations (0.5 x 6 mm) of 183 patients undergoing coronary artery bypass surgery were electrically stimulated at optimal length. Active tension (stimulation) and passive resting tension (relaxation) were measured (measurement conditions: 37 degrees C, Krebs-Henseleit solution, optimal length and supramaximal electrical stimulation). The relationship of body weight with the measured parameters was analyzed statistically by using linear regression model and Student's t-test. RESULTS: Active tension (mN/mm2) and passive resting tension (mN/mm(2)) declined significantly with increasing body weight (p < 0.0001). The ratio passive resting tension/active tension correlated significantly with body weight (p < 0.0001). The negative association between body weight and active tension amplitude was more pronounced in women (p < 0.05). The following linear regression was calculated: for men: force = -0.04 x body weight + 8.74 (R = 0.505, p < 0.0001, n = 106); for women: force = -0.08 x body weight + 12.03 (R = 0.717, p < 0.0001, n = 77). CONCLUSION: The experimental data are in accordance with the hypothesis, that obese tissue may exert a direct cardio-depressant effect on electromechanical coupling.